I recently got a brand new late 2011 15" MacBook Pro; about nine days ago, to be exact. I read on several websites, including Apple's very own support site, that battery calibration is recommended. So I went ahead and did it last night. However, my understanding is that you need to let it sleep for a minimum of FIVE hours. I did it for only three and then plugged the charger back into the MacBook. Maybe I'm being a little paranoid, but does it matter if it's slightly less than the recommended sleep time? Thanks in advance.